package godirwalk

import "github.com/karrick/godirwalk"

Index ¶

• func ReadDirnames(osDirname string, scratchBuffer []byte) ([]string, error)
• func Walk(pathname string, options *Options) error
• type Dirent
• func (de Dirent) IsDir() bool
• func (de Dirent) IsSymlink() bool
• func (de Dirent) ModeType() os.FileMode
• func (de Dirent) Name() string
• type Dirents
• func ReadDirents(osDirname string, scratchBuffer []byte) (Dirents, error)
• func (l Dirents) Len() int
• func (l Dirents) Less(i, j int) bool
• func (l Dirents) Swap(i, j int)
• type Options
• type WalkFunc

Functions ¶

func ReadDirnames ¶

func ReadDirnames(osDirname string, scratchBuffer []byte) ([]string, error)

ReadDirnames returns a slice of strings, representing the immediate descendants of the specified directory. If the specified directory is a symbolic link, it will be resolved.

If an optional scratch buffer is provided that is at least one page of memory, it will be used when reading directory entries from the file system.

Note that this function, depending on operating system, may or may not invoke the ReadDirents function, in order to prepare the list of immediate descendants. Therefore, if your program needs both the names and the file system mode types of descendants, it will always be faster to invoke ReadDirents directly, rather than calling this function, then looping over the results and calling os.Stat for each child.

children, err := godirwalk.ReadDirnames(osDirname, nil)
if err != nil {
    return nil, errors.Wrap(err, "cannot get list of directory children")
}
sort.Strings(children)
for _, child := range children {
    fmt.Printf("%s\n", child)
}

func Walk ¶

func Walk(pathname string, options *Options) error

Walk walks the file tree rooted at the specified directory, calling the specified callback function for each file system node in the tree, including root, symbolic links, and other node types. The nodes are walked in lexical order, which makes the output deterministic but means that for very large directories this function can be inefficient.

This function is often much faster than filepath.Walk because it does not invoke os.Stat for every node it encounters, but rather obtains the file system node type when it reads the parent directory.

func main() {
    dirname := "."
    if len(os.Args) > 1 {
        dirname = os.Args[1]
    }
    err := godirwalk.Walk(dirname, &godirwalk.Options{
        Callback: func(osPathname string, de *godirwalk.Dirent) error {
            fmt.Printf("%s %s\n", de.ModeType(), osPathname)
            return nil
        },
    })
    if err != nil {
        fmt.Fprintf(os.Stderr, "%s\n", err)
        os.Exit(1)
    }
}

Types ¶

type Dirent ¶

type Dirent struct {
	// contains filtered or unexported fields
}

Dirent stores the name and file system mode type of discovered file system entries.

func (Dirent) IsDir ¶

func (de Dirent) IsDir() bool

IsDir returns true if and only if the Dirent represents a file system directory. Note that on some operating systems, more than one file mode bit may be set for a node. For instance, on Windows, a symbolic link that points to a directory will have both the directory and the symbolic link bits set.

func (Dirent) IsSymlink ¶

func (de Dirent) IsSymlink() bool

IsSymlink returns true if and only if the Dirent represents a file system symbolic link. Note that on some operating systems, more than one file mode bit may be set for a node. For instance, on Windows, a symbolic link that points to a directory will have both the directory and the symbolic link bits set.

func (Dirent) ModeType ¶

func (de Dirent) ModeType() os.FileMode

ModeType returns the mode bits that specify the file system node type. We could make our own enum-like data type for encoding the file type, but Go's runtime already gives us architecture independent file modes, as discussed in `os/types.go`:

Go's runtime FileMode type has same definition on all systems, so that
information about files can be moved from one system to another portably.

func (Dirent) Name ¶

func (de Dirent) Name() string

Name returns the basename of the file system entry.

type Dirents ¶

type Dirents []*Dirent

Dirents represents a slice of Dirent pointers, which are sortable by name. This type satisfies the `sort.Interface` interface.

func ReadDirents ¶

func ReadDirents(osDirname string, scratchBuffer []byte) (Dirents, error)

ReadDirents returns a sortable slice of pointers to Dirent structures, each representing the file system name and mode type for one of the immediate descendant of the specified directory. If the specified directory is a symbolic link, it will be resolved.

If an optional scratch buffer is provided that is at least one page of memory, it will be used when reading directory entries from the file system.

children, err := godirwalk.ReadDirents(osDirname, nil)
if err != nil {
    return nil, errors.Wrap(err, "cannot get list of directory children")
}
sort.Sort(children)
for _, child := range children {
    fmt.Printf("%s %s\n", child.ModeType, child.Name)
}

func (Dirents) Len ¶

func (l Dirents) Len() int

Len returns the count of Dirent structures in the slice.

func (Dirents) Less ¶

func (l Dirents) Less(i, j int) bool

Less returns true if and only if the Name of the element specified by the first index is lexicographically less than that of the second index.

func (Dirents) Swap ¶

func (l Dirents) Swap(i, j int)

Swap exchanges the two Dirent entries specified by the two provided indexes.

type Options ¶

type Options struct {
	// FollowSymbolicLinks specifies whether Walk will follow symbolic links
	// that refer to directories. When set to false or left as its zero-value,
	// Walk will still invoke the callback function with symbolic link nodes,
	// but if the symbolic link refers to a directory, it will not recurse on
	// that directory. When set to true, Walk will recurse on symbolic links
	// that refer to a directory.
	FollowSymbolicLinks bool

	// Unsorted controls whether or not Walk will sort the immediate descendants
	// of a directory by their relative names prior to visiting each of those
	// entries.
	//
	// When set to false or left at its zero-value, Walk will get the list of
	// immediate descendants of a particular directory, sort that list by
	// lexical order of their names, and then visit each node in the list in
	// sorted order. This will cause Walk to always traverse the same directory
	// tree in the same order, however may be inefficient for directories with
	// many immediate descendants.
	//
	// When set to true, Walk skips sorting the list of immediate descendants
	// for a directory, and simply visits each node in the order the operating
	// system enumerated them. This will be more fast, but with the side effect
	// that the traversal order may be different from one invocation to the
	// next.
	Unsorted bool

	// Callback is the function that Walk will invoke for every file system node
	// it encounters.
	Callback WalkFunc

	// ScratchBuffer is an optional scratch buffer for Walk to use when reading
	// directory entries, to reduce amount of garbage generation. Not all
	// architectures take advantage of the scratch buffer.
	ScratchBuffer []byte
}

Options provide parameters for how the Walk function operates.

type WalkFunc ¶

type WalkFunc func(osPathname string, directoryEntry *Dirent) error

WalkFunc is the type of the function called for each file system node visited by Walk. The pathname argument will contain the argument to Walk as a prefix; that is, if Walk is called with "dir", which is a directory containing the file "a", the provided WalkFunc will be invoked with the argument "dir/a", using the correct os.PathSeparator for the Go Operating System architecture, GOOS. The directory entry argument is a pointer to a Dirent for the node, providing access to both the basename and the mode type of the file system node.

If an error is returned by the walk function, processing stops. The sole exception is when the function returns the special value filepath.SkipDir. If the function returns filepath.SkipDir when invoked on a directory, Walk skips the directory's contents entirely. If the function returns filepath.SkipDir when invoked on a non-directory file system node, Walk skips the remaining files in the containing directory.

Source Files ¶

readdir.go walk.go

Directories ¶